Ataxin-2 Protein (ATXN2)
Overview <table class="infobox infobox-protein">Lsm domain </td>PAM2 motif </td>PolyQ tract </td>PolyA-binding domain </td>C-terminal </td>Repeat length </td>Onset age </td>Phenotype </td>Neuropathology </td>ASO therapy </td>CRISPR </td>Stress granule modulators </td>Neuroprotective </td>
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Ataxin-2 Protein (ATXN2)
Overview <table class="infobox infobox-protein">Lsm domain </td>PAM2 motif </td>PolyQ tract </td>PolyA-binding domain </td>C-terminal </td>Repeat length </td>Onset age </td>Phenotype </td>Neuropathology </td>ASO therapy </td>CRISPR </td>Stress granule modulators </td>Neuroprotective </td>
Ataxin-2 (encoded by the ATXN2 gene) is a 1,318 amino acid RNA-binding protein with multifaceted roles in RNA metabolism, stress granule dynamics, and translational control. It ispathologically expanded for Spinocerebellar Ataxia Type 2 (SCA2), and intermediate polyglutamine (polyQ) repeat expansions in ATXN2 are a recognized genetic risk factor for amyotrophic lateral sclerosis (ALS) and possibly Parkinson's disease (PD). [@lastorio2020][@gonzalez2019]
Protein Structure
Normal Function Ataxin-2 is predominantly cytoplasmic and participates in:
RNA processing — alternative splicing, mRNA stability [@neuwald1999]Translation regulation — interacts with polyribosomes and translation initiation factors [@kim2019]Stress granule formation — modulates stress-induced RNA granule dynamics [@van2020]Endocytic trafficking — involved in membrane traffickingInsulin signaling — participates in PI3K/Akt pathway modulation
Disease Associations
Spinocerebellar Ataxia Type 2 (SCA2) SCA2 is caused by CAG repeat expansions in ATXN2 (>32 repeats), encoding an expanded polyQ tract:
Amyotrophic Lateral Sclerosis (ALS) Intermediate ATXN2 repeat expansions (27-33 repeats) increase ALS risk:
OR for ALS : 1.5-3.0 for intermediate repeatsPathogenesis : Altered stress granule dynamics, TDP-43 mislocalizationTherapeutic targeting : ASO therapy targeting ATXN2 under developmentParkinson's Disease (PD) Expanded ATXN2 repeats have been associated with PD risk:
Association : Some PD cohorts show increased intermediate repeatsMechanism : May affect α-synuclein expression regulationControversial : Not consistently replicated across populationsPathogenic Mechanisms
Stress Granule Dysregulation WT ataxin-2 localizes to stress granules during cellular stress:
Stress induction — Cellular stress triggers granule formationATXN2 recruitment — Binds to specific mRNAsGranule maturation — Regulates translation repressionResolution — Granule disassembly after stressMutant ataxin-2 disrupts this cycle, leading to:
Persistent stress granule formation
Sequestration of translation components
Impaired protein quality control
Transcriptional Dysregulation Ataxin-2 interacts with:
TDP-43 (TARDBP) — ALS-linked RNA binding proteinFUS — ALS-linked nuclear proteinSMN complex — splicing machineryTherapeutic Approaches
Cross-Links
[ATXN2 Gene](/genes/atxn2)
[Spinocerebellar Ataxia Type 2](/diseases/sca2)
[Amyotrophic Lateral Sclerosis](/diseases/amyotrophic-lateral-sclerosis)
[Parkinson's Disease](/diseases/parkinsons-disease)
[Ataxin-1](/proteins/ataxin-1)
[Stress Granules](/mechanisms/stress-granule-pathology)
[TDP-43 Pathway](/mechanisms/tdp-43-proteinopathy)
References
[Lastorio et al., Ataxin-2 in PD and DLB (2020)](https://pubmed.ncbi.nlm.nih.gov/32880726/)
[Gonzalez et al., ATXN2 intermediate repeats and ALS (2019)](https://pubmed.ncbi.nlm.nih.gov/31167025/)
[Van耶格尔 et al., Ataxin-2 stress granule dynamics (2020)](https://pubmed.ncbi.nlm.nih.gov/32341584/)
[Orr HT, Ataxin-2 function (2012)](https://pubmed.ncbi.nlm.nih.gov/22781292/)
[Kim et al., Ataxin-2 translation regulation (2019)](https://pubmed.ncbi.nlm.nih.gov/31681928/)
[Gao et al., Ataxin-2 RNA granule formation (2022)](https://pubmed.ncbi.nlm.nih.gov/35595678/)
[Luo et al., ATXN2 polyQ and PD (2021)](https://pubmed.ncbi.nlm.nih.gov/34250692/)
[Neuwald et al., Lsm proteins (1999)](https://pubmed.ncbi.nlm.nih.gov/10472013/) Show full description